title: DNAI2 mutations cause primary ciliary dyskinesia with defects in the outer dynein arm.
abstract: Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder characterized by chronic destructive airway disease and randomization of left/right body asymmetry. Males often have reduced fertility due to impaired sperm tail function. The complex PCD phenotype results from dysfunction of cilia of the airways and the embryonic node and the structurally related motile sperm flagella. This is associated with underlying ultrastructural defects that frequently involve the outer dynein arm (ODA) complexes that generate cilia and flagella movement. Applying a positional and functional candidate-gene approach, we identified homozygous loss-of-function DNAI2 mutations (IVS11+1G > A) in four individuals from a family with PCD and ODA defects. Further mutational screening of 105 unrelated PCD families detected two distinct homozygous mutations, including a nonsense (c.787C > T) and a splicing mutation (IVS3-3T > G) resulting in out-of-frame transcripts. Analysis of protein expression of the ODA intermediate chain DNAI2 showed sublocalization throughout respiratory cilia. Electron microscopy showed that mutant respiratory cells from these patients lacked DNAI2 protein expression and exhibited ODA defects. High-resolution immunofluorescence imaging demonstrated absence of the ODA heavy chains DNAH5 and DNAH9 from all DNAI2 mutant ciliary axonemes. In addition, we demonstrated complete or distal absence of DNAI2 from ciliary axonemes in respiratory cells of patients with mutations in genes encoding the ODA chains DNAH5 and DNAI1, respectively. Thus, DNAI2 and DNAH5 mutations affect assembly of proximal and distal ODA complexes, whereas DNAI1 mutations mainly disrupt assembly of proximal ODA complexes.
authors.affiliation: Department of Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg, Germany.
authors.forename: Niki Tomas
authors.initials: NT
authors.lastname: Loges
authors.forename: Heike
authors.initials: H
authors.lastname: Olbrich
authors.forename: Lale
authors.initials: L
authors.lastname: Fenske
authors.forename: Huda
authors.initials: H
authors.lastname: Mussaffi
authors.forename: Judit
authors.initials: J
authors.lastname: Horvath
authors.forename: Manfred
authors.initials: M
authors.lastname: Fliegauf
authors.forename: Heiner
authors.initials: H
authors.lastname: Kuhl
authors.forename: Gyorgy
authors.initials: G
authors.lastname: Baktai
authors.forename: Erzsebet
authors.initials: E
authors.lastname: Peterffy
authors.forename: Rahul
authors.initials: R
authors.lastname: Chodhari
authors.forename: Eddie M K
authors.initials: EM
authors.lastname: Chung
authors.forename: Andrew
authors.initials: A
authors.lastname: Rutman
authors.forename: Christopher
authors.initials: C
authors.lastname: O'Callaghan
authors.forename: Hannah
authors.initials: H
authors.lastname: Blau
authors.forename: Laszlo
authors.initials: L
authors.lastname: Tiszlavicz
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Voelkel
authors.forename: Michal
authors.initials: M
authors.lastname: Witt
authors.forename: Ewa
authors.initials: E
authors.lastname: Zietkiewicz
authors.forename: Juergen
authors.initials: J
authors.lastname: Neesen
authors.forename: Richard
authors.initials: R
authors.lastname: Reinhardt
authors.forename: Hannah M
authors.initials: HM
authors.lastname: Mitchison
authors.forename: Heymut
authors.initials: H
authors.lastname: Omran
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D002648:Child; D002675:Child, Preschool; D002923:Cilia / Q000235:genetics* / Q000648:ultrastructure; D003241:Consanguinity; D004252:DNA Mutational Analysis; D004398:Dyneins / Q000737:chemistry / Q000235:genetics* / Q000648:ultrastructure*; D005091:Exons; D005260:Female; D005407:Flagella / Q000235:genetics; D005787:Gene Frequency; D008040:Genetic Linkage; D006801:Humans; D007619:Kartagener Syndrome / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide; D012326:RNA Splicing; D017422:Sequence Analysis, DNA; D055815:Young Adult
chemical_list: D004398:Dyneins